- 06 Jan, 2009 40 commits
-
-
Chuck Lever authored
Clean up: one last thing... relocate nsm_create() to eliminate the forward declaration and group it near the only function that actually uses it. Signed-off-by:
Chuck Lever <chuck.lever@oracle.com> Signed-off-by:
J. Bruce Fields <bfields@citi.umich.edu>
-
Chuck Lever authored
Clean up. Treat the nsm_use_hostnames global variable like nsm_local_state. Note that the default value of nsm_use_hostnames is still zero. Signed-off-by:
-
Chuck Lever authored
Clean up: nsm_addr_in() is no longer used, and nsm_addr() is used only in fs/lockd/mon.c, so move it there. Signed-off-by:
-
Chuck Lever authored
Clean up: The include/linux/lockd/sm_inter.h header is nearly empty now. Remove it. Signed-off-by:
-
Chuck Lever authored
NLM provides file locking services for NFS files. Part of this service includes a second protocol, known as NSM, which is a reboot notification service. NLM uses this service to determine when to reclaim locks or enter a grace period after a client or server reboots. The NLM service (implemented by lockd in the Linux kernel) contacts the local NSM service (implemented by rpc.statd in Linux user space) via NSM protocol upcalls to register a callback when a particular remote peer reboots. To match the callback to the correct remote peer, the NLM service constructs a cookie that it passes in the request. The NSM service passes that cookie back to the NLM service when it is notified that the given remote peer has indeed rebooted. Currently on Linux, the cookie is the raw 32-bit IPv4 address of the remote peer. To support IPv6 addresses, which are larger, we could use all 16 bytes of the cookie to represent a full IPv6 address, although we still can't represent an IPv6 address with a scope ID in just 16 bytes. Instead, to avoid the need for future changes to support additional address types, we'll use a manufactured value for the cookie, and use that to find the corresponding nsm_handle struct in the kernel during the NLMPROC_SM_NOTIFY callback. This should provide complete support in the kernel's NSM implementation for IPv6 hosts, while remaining backwards compatible with older rpc.statd implementations. Note we also deal with another case where nsm_use_hostnames can change while there are outstanding notifications, possibly resulting in the loss of reboot notifications. After this patch, the priv cookie is always used to lookup rebooted hosts in the kernel. Signed-off-by:
-
Chuck Lever authored
Clean up: refactor nsm_get_handle() so it is organized the same way that nsm_reboot_lookup() is. There is an additional micro-optimization here. This change moves the "hostname & nsm_use_hostnames" test out of the list_for_each_entry() clause in nsm_get_handle(), since it is loop-invariant. Signed-off-by:
-
Chuck Lever authored
Clean up. Refactor the creation of nsm_handles into a helper. Fields are initialized in increasing address order to make efficient use of CPU caches. Signed-off-by:
-
Chuck Lever authored
Clean up: nsm_find() now has only one caller, and that caller unconditionally sets the @create argument. Thus the @create argument is no longer needed. Since nsm_find() now has a more specific purpose, pick a more appropriate name for it. Signed-off-by:
-
Chuck Lever authored
Invoke the newly introduced nsm_reboot_lookup() function in nlm_host_rebooted() instead of nsm_find(). This introduces just one behavioral change: debugging messages produced during reboot notification will now appear when the NLMDBG_MONITOR flag is set, but not when the NLMDBG_HOSTCACHE flag is set. Signed-off-by:
-
Chuck Lever authored
Introduce a new API to fs/lockd/mon.c that allows nlm_host_rebooted() to lookup up nsm_handles via the contents of an nlm_reboot struct. The new function is equivalent to calling nsm_find() with @create set to zero, but it takes a struct nlm_reboot instead of separate arguments. Signed-off-by:
-
Chuck Lever authored
The NLM XDR decoders for the NLMPROC_SM_NOTIFY procedure should treat their "priv" argument truly as an opaque, as defined by the protocol, and let the upper layers figure out what is in it. This will make it easier to modify the contents and interpretation of the "priv" argument, and keep knowledge about what's in "priv" local to fs/lockd/mon.c. For now, the NLM and NSM implementations should behave exactly as they did before. The formation of the address of the rebooted host in nlm_host_rebooted() may look a little strange, but it is the inverse of how nsm_init_private() forms the private cookie. Plus, it's going away soon anyway. Signed-off-by:
-
Chuck Lever authored
Pass the nlm_reboot data structure directly from the NLMPROC_SM_NOTIFY XDR decoders to nlm_host_rebooted(). This eliminates some packing and unpacking of the NLMPROC_SM_NOTIFY results, and prepares for passing these results, including the "priv" cookie, directly to a lookup routine in fs/lockd/mon.c. This patch changes code organization but should not cause any behavioral change. Signed-off-by:
-
Chuck Lever authored
Pass the new "priv" cookie to NSMPROC_MON's XDR encoder, instead of creating the "priv" argument in the encoder at call time. This patch should not cause a behavioral change: the contents of the cookie remain the same for the time being. Signed-off-by:
-
Chuck Lever authored
Introduce a new data type, used by both the in-kernel NLM and NSM implementations, that is used to manage the opaque "priv" argument for the NSMPROC_MON and NLMPROC_SM_NOTIFY calls. Construct the "priv" cookie when the nsm_handle is created. The nsm_init_private() function may look a little strange, but it is roughly equivalent to how the XDR encoder formed the "priv" argument. It's going to go away soon. Signed-off-by:
-
Chuck Lever authored
The nsm_release() function should never be called with a NULL handle point. If it is, that's a bug. Signed-off-by:
-
Chuck Lever authored
The nsm_find() function should never be called with a NULL IP address pointer. If it is, that's a bug. Signed-off-by:
-
Chuck Lever authored
Introduce some dprintk() calls in fs/lockd/mon.c that are enabled by the NLMDBG_MONITOR flag. These report when we find, create, and release nsm_handles. Signed-off-by:
-
Chuck Lever authored
The nsm_find() function sets up fresh nsm_handle entries. This is where we will store the "priv" cookie used to lookup nsm_handles during reboot recovery. The cookie will be constructed when nsm_find() creates a new nsm_handle. As much as possible, I would like to keep everything that handles a "priv" cookie in fs/lockd/mon.c so that all the smarts are in one source file. That organization should make it pretty simple to see how all this works. To me, it makes more sense than the current arrangement to keep nsm_find() with nsm_monitor() and nsm_unmonitor(). So, start reorganizing by moving nsm_find() into fs/lockd/mon.c. The nsm_release() function comes along too, since it shares the nsm_lock global variable. Signed-off-by:
-
Chuck Lever authored
Introduce xdr_stream-based XDR encoder and decoder functions, which are more careful about preventing RPC buffer overflows. Signed-off-by:
-
Chuck Lever authored
Clean up: Move the RPC program and procedure numbers for NSM into the one source file that needs them: fs/lockd/mon.c. And, as with NLM, NFS, and rpcbind calls, use NSMPROC_FOO instead of SM_FOO for NSM procedure numbers. Finally, make a couple of comments more precise: what is referred to here as SM_NOTIFY is really the NLM (lockd) NLMPROC_SM_NOTIFY downcall, not NSMPROC_NOTIFY. Signed-off-by:
-
Chuck Lever authored
Clean up: NSM's XDR data structures are used only in fs/lockd/mon.c, so move them there. Signed-off-by:
-
Chuck Lever authored
Make sure any error returned by rpc.statd during an SM_UNMON call is reported rather than ignored completely. There isn't much to do with such an error, but we should log it in any case. Similar to a recent change to nsm_monitor(). Signed-off-by:
-
Chuck Lever authored
Clean up. Make the nlm_host argument "const," and move the public declaration to lockd.h. Add a documenting comment. Bruce observed that nsm_unmonitor()'s only caller doesn't care about its return code, so make nsm_unmonitor() return void. Signed-off-by:
-
Chuck Lever authored
The nsm_handle's reference count is bumped in nlm_lookup_host(). It should be decremented in nlm_destroy_host() to make it easier to see the balance of these two operations. Move the nsm_release() call to fs/lockd/host.c. The h_nsmhandle pointer is set in nlm_lookup_host(), and never cleared. The nlm_destroy_host() function is never called for the same nlm_host twice, so h_nsmhandle won't ever be NULL when nsm_unmonitor() is called. All references to the nlm_host are gone before it is freed. We can skip making h_nsmhandle NULL just before the nlm_host is deallocated. It's also likely we can remove the h_nsmhandle NULL check in nlmsvc_is_client() as well, but we can do that later when rearchitect- ing the nlm_host cache. Signed-off-by:
-
Chuck Lever authored
Clean up. Make the nlm_host argument "const," and move the public declaration to lockd.h with other NSM public function (nsm_release, eg) and global variable declarations. Add a documenting comment. Signed-off-by:
-
Chuck Lever authored
The nsm_monitor() function reports an error and does not set sm_monitored if the SM_MON upcall reply has a non-zero result code, but nsm_monitor() does not return an error to its caller in this case. Since sm_monitored is not set, the upcall is retried when the next NLM request invokes nsm_monitor(). However, that may not come for a while. In the meantime, at least one NLM request will potentially proceed without the peer being monitored properly. Have nsm_monitor() return an error if the result code is non-zero. This will cause all NLM requests to fail immediately if the upcall completed successfully but rpc.statd returned an error. This may be inconvenient in some cases (for example if rpc.statd cannot complete a proper DNS reverse lookup of the hostname), but will make the reboot monitoring service more robust by forcing such issues to be corrected by an admin. Signed-off-by:
-
Chuck Lever authored
Clean up: Remove the BUG_ON() invocation in nsm_monitor(). It's not likely that nsm_monitor() is ever called with a NULL host pointer, and the code will die anyway if host is NULL. Signed-off-by:
-
Chuck Lever authored
The nsm_monitor() function already generates a printk(KERN_NOTICE) if the SM_MON upcall fails, so the similar printk() in the nlmclnt_lock() function is redundant. Signed-off-by:
-
Chuck Lever authored
Clean up: Use the sm_name field for reporting the hostname in nsm_monitor() and nsm_unmonitor(), just as the other functions in fs/lockd/mon.c do. The h_name field is just a copy of the sm_name pointer. Signed-off-by:
-
Chuck Lever authored
The "mon_name" argument of the NSMPROC_MON and NSMPROC_UNMON upcalls is a string that contains the hostname or IP address of the remote peer to be notified when this host has rebooted. The sm-notify command uses this identifier to contact the peer when we reboot, so it must be either a well-qualified DNS hostname or a presentation format IP address string. When the "nsm_use_hostnames" sysctl is set to zero, the kernel's NSM provides a presentation format IP address in the "mon_name" argument. Otherwise, the "caller_name" argument from NLM requests is used, which is usually just the DNS hostname of the peer. To support IPv6 addresses for the mon_name argument, we use the nsm_handle's address eye-catcher, which already contains an appropriate presentation format address string. Using the eye-catcher string obviates the need to use a large buffer on the stack to form the presentation address string for the upcall. This patch also addresses a subtle bug. An NSMPROC_MON request and the subsequent NSMPROC_UNMON request for the same peer are required to use the same value for the "mon_name" argument. Otherwise, rpc.statd's NSMPROC_UNMON processing cannot locate the database entry for that peer and remove it. If the setting of nsm_use_hostnames is changed between the time the kernel sends an NSMPROC_MON request and the time it sends the NSMPROC_UNMON request for the same peer, the "mon_name" argument for these two requests may not be the same. This is because the value of "mon_name" is currently chosen at the moment the call is made based on the setting of nsm_use_hostnames To ensure both requests pass identical contents in the "mon_name" argument, we now select which string to use for the argument in the nsm_monitor() function. A pointer to this string is saved in the nsm_handle so it can be used for a subsequent NSMPROC_UNMON upcall. NB: There are other potential problems, such as how nlm_host_rebooted() might behave if nsm_use_hostnames were changed while hosts are still being monitored. This patch does not attempt to address those problems. Signed-off-by:
-
Chuck Lever authored
Clean up: I'm about to add another "char *" field to the nsm_handle structure. The sm_name field uses an older style of declaring a "char *" field. If I match that style for the new field, checkpatch.pl will complain. So, fix the sm_name field to use the new style. Signed-off-by:
-
Chuck Lever authored
Clean up: make the printk(KERN_DEBUG) in nsm_mon_unmon() a dprintk, and add another dprintk to note if creating an RPC client for the upcall failed. Signed-off-by:
-
Chuck Lever authored
Clean up: Use a C99 structure initializer instead of open-coding the initialization of nsm_args. Signed-off-by:
-
Chuck Lever authored
Clean up: introduce a helper function to generate IPv4 addresses using the same style as the IPv6 helper function we just added. Signed-off-by:
-
Chuck Lever authored
Scope ID support is needed since the kernel's NSM implementation is about to use these displayed addresses as a mon_name in some cases. When nsm_use_hostnames is zero, without scope ID support NSM will fail to handle peers that contact us via a link-local address. Link-local addresses do not work without an interface ID, which is stored in the sockaddr's sin6_scope_id field. Signed-off-by:
-
Chuck Lever authored
AF_UNSPEC support is no longer needed in nlm_display_address() now that a presentation address is no longer generated for the h_srcaddr field. Signed-off-by:
-
Chuck Lever authored
The h_name field in struct nlm_host is a just copy of h_nsmhandle->sm_name. Likewise, the contents of the h_addrbuf field should be identical to the sm_addrbuf field. The h_srcaddrbuf field is used only in one place for debugging. We can live without this until we get %pI formatting for printk(). Currently these buffers are 48 bytes, but we need to support scope IDs in IPv6 presentation addresses, which means making the buffers even larger. Instead, let's find ways to eliminate them to save space. Signed-off-by:
-
Chuck Lever authored
Clean up: I'm about to add another "char *" field to the nlm_host structure. The h_name field, for example, uses an older style of declaring a "char *" field. If I match that style for the new field, checkpatch.pl will complain. So, fix pointer fields to use the new style. Signed-off-by:
-
Jeff Layton authored
The default method for calculating the number of connections allowed per RPC service arbitrarily limits single-threaded services to 80 connections. This is too low for services like lockd and artificially limits the number of TCP clients that it can support. Have lockd set a default sv_maxconn value to 1024 (which is the typical default value for RLIMIT_NOFILE. Also add a module parameter to allow an admin to set this to an arbitrary value. Signed-off-by:
Jeff Layton <jlayton@redhat.com> Acked-by:
Neil Brown <neilb@suse.de> Signed-off-by:
-
Jeff Layton authored
svc_check_conn_limits() attempts to prevent denial of service attacks by having the service close old connections once it reaches a threshold. This threshold is based on the number of threads in the service: (serv->sv_nrthreads + 3) * 20 Once we reach this, we drop the oldest connections and a printk pops to warn the admin that they should increase the number of threads. Increasing the number of threads isn't an option however for services like lockd. We don't want to eliminate this check entirely for such services but we need some way to increase this limit. This patch adds a sv_maxconn field to the svc_serv struct. When it's set to 0, we use the current method to calculate the max number of connections. RPC services can then set this on an as-needed basis. Signed-off-by:
-
